UC-NRLF

SB 573

in

oo

o

LIBRARYOF THE

UNIVERSITY OF CALIFORNIA.

Class

m

"The simplest natural objects have bearings which calculation does not

touch, and appearances and relations which definition fails to include."

General Specifications

FOB

Steel Roofs and Buildings.

FOURTH REVISED EDITION.

With Tables.

19OI

CHARLES EVAN FOWLER,M. Am. Soc. E.

N*v

fc&UFQf^

Diagram.

*y:GENERAL SP&GIFIGftTIONS FOR STEEL

ROOFS flND BUILDINGS.

CHARLES EVAN FOWLER, M. AM. Soc. C. E.

FOURTH REVISED EDITION

1899-

GENERAL DESCRIPTION.

1. The structure shall be of the general outline and dimen-

sions shown on the attached diagram, which gives the principal

dimensions and all the principal data. (2, 72.)

2. The sizes and sections of all members, together with the

strains which come upon them, shall be marked in their

proper places upon a strain sheet, and submitted with proposal.

(X 72.)

3. The height of the building shall mean the distance from clearances,

top of masonry to under -side of bottom chord of truss. Thewidth and length of building shall mean the extreme distance

out to out of framing or sheeting.

4. The pitch of roof shall generally be one fourth. (6.)

LOADS.The trusses shall be figured to carry the following loads:

5. SNOW LOADS.

ering

Weight of cov- 8. The weight of covering may be taken as .follows: Cor-

rugated iron laid, black and painted, per square foot:

No. 27 26 24 22 20 18 16

.90 i.oo 1.30 i.60 1.90 2.60 3. 30 pounds.For galvanized iron add 0.2 pounds per square foot to above

figures.

Slate shall be taken at a weight of 7 pounds per square foot

for 3-16" -slate 6" x 12", and 8.25 pounds per square foot for

3-16" slate I2"x24", and proportionately for other sizes.

Sheeting of dry pine boards at three pounds per" foot board

measure.

Plastered ceiling hung below at not less than 10 pounds per

square foot.

The exact weight of purlins shall be calculated.

9. The weight of Fink roof trusses up to 200 feet span

may be calculated by the following formulas, for preliminary value.

w=.c6 s-j-,6, for heavy loads.

w=.Q4 S+.4, for light loads. (40, 45.)

s=span in feet. w= weight per hor. sq. ft. in pounds.

10. Mill buildings, or any that are subject to corrosive action

of gases, shall have all the above loads increased 25 per cent.

11. Buildings or parts of buildings subject to strains from

machinery or other loads not mentioned, shall have the proper

allowance made.

12. No roof shall, however, be calculated for a less load than

30 pounds per horizontal square foot.

Weight of

Trusses

Increase of

Loads.

MinimumLoad.

UNIT STRAINS.

Iron.

Tension only. j^. Shapes, net section , . . .

Bars 14000Bottom flanges of rolled beamsLaterals of angles, net section .

Laterals of bar 18000

Soft-Medium.

Steel

1500017000150002000O

(57)

(57)uo

Compressiononly.

Flanges.

"Combined.

14. Flat ends and fixed ends . , ,. . 12500^500

f

/=length in feet c. to c. of connections.

r least radius of gyration in inches. (59)

15. Top flanges of built girders shall have the same gross

area as tension flanges. (24)

16. Members subject to transverse loading in addition to

direct strain, such as rafters, and posts having knee braces con-

nected to them, shall be considered as fixed at the ends in rivit-

ed work, and shall be proportioned by the following formulae, and

the unit strain in extreme fibre shall not exceed for soft medium

steel: 15000

Ma P^ _ _ _i_ _,

I A (52, 62.)5 =Strain per square inch in extreme fibre.

M Moment of transverse force in inch pounds,n Distance center of gravity to top or bottom of final section

in inches.

I Final moment of inertia.

P -Direct load.

A Final area.Soft-Medium

Soft Steel. Steel.Sheari

17. Pins and rivets ..... 10000 (57)Web plates ...... 7000

18. On ciia. of pins and rivet holes 20000 20000 (57)*

19. Extreme fibre of pins . . . 25000Extreme fibre of purlins . . 15000 (49)

20. Lateral connections will have 25 per cent greater unit

strains than above.

21. Bolts may be used for field connections at two-thirds of Bolts -

rivet values. (17, 18.)

TIMBER PURLINS

22. In purlins of yellow pine, southern pine or white oak,Timber-

the extreme fibre strain shall not exceed 1200 Ibs. sq. iri. (50)

PLATE GIRDERS.

23. The length of span shall be considered as the distanceGirders -

from, center to center of end bearings when girders rest on

bottom flange, and from end to end when fastened betweencolumns by connection angles.

24. The compression flanges shall be stayed transverselyF ian es -

when their length 'is more than thirty times their width. (15)One-sixth of the web shall be included as flange area, provided

proper horizontal splices are made at web joints.

25. All web plates shall be stiffened at the inner and outer stiffeners.

edges of the end bearings and at all points of local concentrated

loading.

Intermediate stiffeners shall be used provided the shearingstrain per square inch exceeds that given by the formula:

15000d* d= Clear dist. between flange angles in inches.

i -|---- t Thickness of web in inches.

3000/2

CORRUGATED IRON COVERING.

26. Corrugated iron shall generally be of 2^ inch corruga-tions, and the gage in U. S. standard shall be shown on strain

sheet,

27. The span or distance center to center of roof purlinsshall not exceed that given in the following table:

27 gage . . . 2' o" 20 gage . . . 4' 6"26 gage .. . . 2' 6" iSgage . . . $'o"24 gage . . . 3' o" 16 gage , . , 5' 6"22 gage . . . 4' o" (48)

28. All corrugated iron shall be laid with one corrugationside lap, and not less than four inches end lap, generally withsix inches end lap. (32)

29. AH valleys or junctions shall have flashing extending atleast 12 inches under the corrugated iron,or 12 inches above linewhere water will stand. (35, 36.)

30. All ridges shall have roll cap securely fastened over the

corrugated iron.Fastenings 3^ Corrugated iron shall preferably be secured to the purlin

by galvanized straps of not less than five-eighths of an inch wideby No. 18 gage; these shall pass completely around the purlin,and have each end riveted to the sheet. There shall be at leasttwo fastenings on each purlin for each sheet.

32. The side laps shall be riveted with six pound rivets notmore than six inches apart. (28.)

Finish An ffie^$. At the gable ends the corrugated iron shall be securely

fastened down on the roof, to a finish angle or channel, connect-ed to the end of the roof purlins.

VENTILATORS AND LOUVRES.Ventilators

34. Ventilators shall be provided and located so as to properlyventilate the building. They shal! have a net area of openingsfor each 100 square feet of floor surface of not less than one-half a square foot for machine shops, of not less than five squarefeet for mill buildings and not less than seven square feet for

forge shops.louvres Louvres shall be provided in ventilators, if necessary, of such

form as to prevent the blowing in of snow or storm watet, and of

a stiff enough section not to sag below hoizontal and appear un-

sightly. They shall be not less than No. 16 gage galvanizedfor flat louvres* and No. 20 gage galvanized for corrugated lou-

vres.

LIGHTING.

windows 35. Windows shall be provided in the sides and clearstory or

ventilator of a surface equal to not less than 10 per cent of the

entire exterior surface of the buildings, in mill buildings, and of

not less than 20 per cent in machine .shops or similiar build-

ings. (29)

Skylights 36. At least half of the lighting specified shall preferablybe in the form of skylights of some form of construction whichshall entirely prohibit leaking. (29)

5

DETAILS OF CONSTRUCTION.

37. All tension members shall preferably be composed of Tension Mem-

angles or shapes with the object of stiffness.bers*

38. All joints shall have full splices and not rely on gussets.

(650

39. All main members shall preferably be made of two angles,back to back, two angles and one plate, or four angles laced. (67.)

40. Secondary members shall preferably be' made of sym-metrical sections.

41. Long laterals or sway rods may be made of bar, withsleeve nut adjustment, to facilitate erection.

42. Members having such a length as to cause them to sagshall be held up by sag ties of angles, properly spaced.

43. Rafters shall preferably be made of two angles, two Compression

angles and one plate, or of such form as to allow of easy connec-tion for web members. (65.)

44. All other compression members, except sub-struts, shall

be composed of sections symmetrically disposed. (65.)

45. Sub-struts shall preferably be made of symmetrical sec-

tions.

46. The trusses shall be spaced, if possible, at such distances Purlin9 -

apart as to allow of single pieces of shape iron being used for

purlins, trussed purlins being avoided, if possible. Purlins shall

preferably be composed of single angles, with the long leg verti-

cal and the back toward the peak of the roof.

47. Purlins shall be attached to the rafters or columns byclips, with at least two rivets in rafter and two holes for each endof each purlin.

48. Roof purlins shall be spaced at distances apart not to ex-ceed the span given under the head of Corrugated Iron. (27.)

49. Purlins extending in one piece over two or more panels,laid to break joint, and riveted at ends, may be figured as con-tinuous.

50. Timber purlins, if used, shall be attached in the samemanner as steel purlins.

51. Sway bracing shall be introduced at such points as is sway Bracing-

necessary to insure ease of erection and sufficient transverse andlongitudinal strength. (41.)

52. All such strains shall preferably be carried to the founda-tion direct, but may be accounted for by bending in the columns.

(62.)

$3. Bed plates shall never be less thar one-half inch in Bed Plates,

thickness, and shall be of sufficient thickness and size so thatthe pressure on masonry will not exceed 300 pounds per squareinch. Trusses over 75 feet span on walls or masonry shall haveexpansion rollers if necessary. (54.)

Punching and

Reaming1

.

Effective

Diameter of

Rivets.

Pitch of

Rivets.

Anchor Bolts. 54. Each bearing plate shall be provided with two anchor

bolts of not less than three-fourths of an inch in diameter, either

built into the masonry or extending far enough into the masonryto make them effective. (53.)

Punching. 55, The diameter of the punch shall not exceed the diamter

of the rivet, nor the diameter of the die exceed the diameter of

the punch by more than one-sixteenth of an inch. (56.)

56. All rivet holes in steel may be punched, and in case holes

do not match in assembled members they shall be reamed out

with power reamers. (71.)

57. The effective diameter of the driven rivet shall be as-

sumed the same as before driving, and in making deductions for

rivet holes in tension members, the hole will be assumed one

eighth of an inch larger than the undriven rivet. (13,17.)

58. The pitch of rivets shall not exceed twenty times the

thickness of the plate in the line of strain, nor forty times the

thickness at right angles to the line of strain. It shall never beless than three diameters of the1

rivet. At the ends of compres-sion members it shall not exceed four diameters of the rivet for a

length equal to the width of the members.

$9. No compression member shall have a length exceedingfifty times its least width, unless its unit strain is reduced

accordingly. (14-)

60. Laced compression members shall be stayed at the ends

by batten plates having a length not less than the depth of the

member.

61. The sizes of lacing bars shall not be less than that givenin the following table, when the distance between the gagelines is (62.)

6" or less than 8" .

8" or less than 10" .

10" or less than 12" . .

12" or less than 16" . .

16" or less than 20" .

20" or less than 24" . .

24" or above of angles.

They shall generally be inclined at 45 degress to the axis of

the member, but shall not be spaced so as to reduce the strengthof the member as a whole.

62. Where laced members are subjected to bending, the size

of lacing bars or angles shall be calculated or a solid Veb plateused. (13, 14, 61.)

63. All rods having screw ends shall be upset to standard size,

or have due allowance made.

64. No. metal of less thickness than ^ inch shall be used,

except as fillers, and no angles of less than 2 inch leg. A varia-

tion of 3 per cent shall be allowable in the weight or cross sec-

tion of material.

I 1-4" x 1-4"I I-2"X 1-4"1 3-4" x 5-16"2" x 3-8"2 1-4" x 7-16"

WORKMANSHIP.

65. All workmanship shall be first class in every particular.All abutting surfaces of compression members, except wherethe joints are fully spliced, must be planed to even bearingso as to give close contact throughout. (38.)

66. All planed or turned surfaces left exposed must be pro-tected by white lead and tallow. (89)

67. Rivet holes for splices must be so accurately spaced that Rivet8

the holes will, come exactly opposite when the members are

brought into position for driving rivets, or else reamed out.

(38, 70, 71.)

68. Rivets must completely fill the holes and have full headsconcentric with the rivet holes. They shall have full contact with

the surface, or b countersunk when so required, and shall bemachine driven When possible. Rivets must not be used in

direct tension.

69. Built members when finished must be free from twists,

open joints or other defects. (65.)

70. Drift pins must only be used for bringing the pieces to- Drillln**

gether, and they must not be driven so hard as to distort the

metal. (71.)

71. When holes need enlarging, it must be done by ream- Rcami -

ing and not by drifting. (70.)

72. The decision of the engineer or architect shall control as Drawings and

as to the interpretation of the drawings and specifications duringspeclfi<

the progress of the work. But this shall not deprive thecontractor of right of redress after work is completed, if the de-

cision shall be proven wrong, (i, 91,95.)

QUALITY OF MATERIAL.

WROUGHT IRON

73. All wrought iron must be tough, ductile, fibrous and of c*a.

r*c*er and

uniform quality. Finished bars must be thoroughly weldedduring the rolling, and be straight, smooth and free from in-

jurious seams, blisters, buckles, cracks or imperfect edges.

74. No one process of manufacture is preferred over another,Manufacture,

provided the material complies with this specification.

75. For tension tests the test piece shall have as near one- standard Test

half square inch of sectional area as possible, and a length of atPleces>

least 8 inches with uniform section, for determining the elongation.76. The elastic limit shall be not less than 26,000 pounds per Elastic Limit

square inch for all classes of iron.

77. Standard test pieces from iron having a section of 4^ Teasion Iron

square inches or less shall show an ultimate strength of not lessthan 50,000 pounds per square inch and an elongation in 8 inchesof not less than 18 per cent.

8

78. Standard test pieces from bars of more than 4^ squareinches section will be allowed a reduction of 500 pounds for

each additional square inch of section, provided the ultimate

strength does not fall below 48,000 pounds or the elongation in

8 inches below 15 per cent.

79. All iron for tension members must bend cold through90 degrees to a curve whose diameter is not over twice thethickness of the piece, without cracking.

80. Not less than one sample out of three shall bend cold tothis curve through 180 degrees, without cracking.

81. When nicked on one side and bent by a blow from a

sledge, the fracture must be wholly fibrous.

STEEL.

Manufacture. 82. Steel made either by the Bessemer or Open Hearth pro-cess of manufacture shall be acceptable.

8 3* Test Pieces for tension and bending tests shall have asnear one-half square inch of sectional area as possible and a

length of at least 8 inches with uniform section, for determimingelongation.

84. One test piece for tension and one for bending are to betaken from each heat or blow of finished material.

Finish.. 85. Finished bars must be free from flaws, cracks or injuriousseams and have a first-class finish.

Gradesgof^ g t Steel of soft and soft-medium grades only are to be used,

the soft steel for rivets and offset or bent angles or plates, andsoft-medium for all other parts where iron is not optional.

Phosphorus The phosphorus shall never exceed in any steel 0.08 per cent.,ndLimu

phnr nor the sulphur 0.04 per cent. (56.)

soft steei. 87. Standard test pieces of finished material shall have anultimate strength of from 50,000 to 60,000 pounds per squareinch; an elastic limit of one-half the ultimate strength; an

elongation in 8 inches of not less than 25 per cent; and a

reduction of area at fracture of not less than 50 per cent.

Samples to bend cold 180 degrees flat on itself, without sign of

fracture on the outside bent portion.soft-Medium 88. Standard test pieces of finished material shall have an

steei.ultimate strength of from 55,000 to 65,000 pounds per squareinch; elastic limit not less than one-half the ultimate strength;an elongation in 8 inches of not less than 25 per cent.; and a

deduction of area at fracture of not less than 50 per cent. Samplesto bend cold 180 degrees to a diameter equal to the thickness of

the sample without crack or flaw on fhe outside of the bent

portion.

PAINTING.

Painting. 89. All iron or steel framing and all corrugated iron, unless

galvanized, shall have one coat of pure lead paint before leavingthe shop; all surfaces in contact shall have one heavy

9coat of pure lead paint before assembling, and all planed or

turned surfaces shall be coated with white lead and tallow (66.)

90. Parts difficult of access after erectiion shall have twocoats of pure lead paint at the shop.

91. After erection all the work except galvanized iron shall

receive one coat of pure lead paint of such shade as the engineeror architect may select, and it shall be thoroughly and evenly

applied. (72,95-)

ERECTION.

92. The contractor will furnish all tools, derricks or staging Erection,

and material of every description for the erection of the whole or

such portions of the work as are included in the contract, andremove the same when the work is completed, leaving the prem-ises as free from rubbish or obstruction as when the erection wascommenced.

93. The contractor shall assume all risks from storms or acci-

dents to the work, unless caused by the negligence or interfer-

ence of the owner or his employees; also all damage to personsand properties and casualties of every description, until the

final acceptance of the completed structure.

94. The contractor shall comply with all ordinances or reg-ulations of the authorities having jurisdiction over the premises or

abutting premises.

95. The erection is to be carried on subject to the approvaland inspection of the engineer or architect, and it is to be com-

pleted to his satisfaction and in full accordance with the

contract. (72,91.)

^7\BRAOF THE

UNIVtK3ITYOF

10 COEFFICIENTS FOR ROOF TRUSSES.

s -

?rcx\V ~\vtxss.

P<xwe\s. P

n= s= *

h pitchs=span, h=height. P= panel load.

fcompression. tension. Strain in member = Px coefficient.

Load on wall or column= Reaction+o.gP.

PRATT TRUSS, EIGHT PANELS.

Member

PRATT TRUSS, FOUR PANELS. ii

PRATT TRUSS, SIX PANELS.

Member

COEFFICIENTS FOR ROOF TRUSSES.

Compound Fintf Truss

Compound Fan Truss.

S span

s= span, h == height. P = panel load, n = =pjj^ -|- compression. tension.

Strain in member= P X coefficient. Load on wall orcolumn~= Reaction -]-o.5 P

COMPOUND FINK ,TRUSS.

Member.

Ba

La

ab

Cb

be

Lc

cd

De

ed

ef

fe

Ef

6.31

5-25

0.83

0-75

4-50

1.66

5.20

o-75

3.00

1-50

0.83

2.25

4-65

=4

7.83

7.00

0.89

7-38

1.006.00

1.79

6-93

I.OO

4.002.0O

0.89

3.00

6.48

*=5

9.42

8-75

o-93

9-05

1.25

7-50

1.86

8.68

1.25

5.00

2.50

0-93

3-75

8.31

General Formulae.

\n2n

n

XPXP

XP

XP

XPXP

XP

XPXPXP

XP

XP

XP

SIMPLE FINK TRUSS.

Member.

SIMPLE FAN TRUSS.

Member.

INDEX.

Acceptance, 72, 95. Imperfections, 73, 85. Sways, 41, 51, 52.Architect, 72, 91, 95. Span, 23, 27, 46.Anchors, 54. Joints, 24, 38, 65. Strain Sheet, i, 2, 72.

Slate, 8.

Bars, 13, 41, 63, 77,78, 79, Lacing, 60, 61, 62. Shapes, 13, 87, 88.

80, 81, 85, 87, 88. Lap, 28. Sag Ties, 42.Battens, 60. Laterals, 13, 20, 41. Secondary Members, 40,Bessemer Steel, 82. Lateral Connections,2o, 44, 45.Bearing, 18, 53, 65. 41. Sheeting, 8.

Beams, 13. Lighting, 35, 36. Shearing, 17.

Bending, 16, 19, 52,62,86, Loads,5,6,7,8,9,10,11, 12 Screw, 63.Bed Plates, 53. Louvres, 34. Steel, 82, 83, 84, 85, 86,Boards, 6. 87, 88,Bolts, 21, 54. Machinery, n. Stiffeners, 25.Built Members, 69. Machine Shops,i 1,34,35. Splices, 24, 38, 65, 67.

Main Members,39,43,44. Snow, 34.

Clips, 31/47. Masonry, 3, 52, 53, 54. Snow Load, 5.

Corrosion, 10.. y Mill Buildings, 10, n, Soft Steel, 86, 87.

Columns, 14, 42, 44. 34, 35. Soft-Medium Steel, 86,Compression Members, 14, Minimum Loads, 10, 11. 88.

24, 43, 44, 45, 52, 58, 12. Sub-Struts, 44, 45.

59,60,61,65,66,69. Sulphur, 86.

Completion, 95. Offsetting, 86. Skylights, 36.Combined Strains, 16. Open Hearth Steel, 82.

Corrugated Iron, 8, 26,27, Test Pieces, 75, 83, 84.

28, 31, 32, 33-, 89, 91. Plate Iron. 87, 88. Tension Members, 13,

Contractor, 72,93, 94. Painting, 66, 90, 91. 16,24, 37, 38, 3^,

Planing, 65, 66, 89. 40, 41, 42, 57, 68.

Damage, 92, 93, 94, 95, Plaster, 8. Timber, 22, 50.

Drawings, i, 2, 72. Plate Girders, 13, 15,17, Tie Plates, 60.

Decisions, 72. - 23, 24, 25. Tools, 92.

Diagram, i, 2, 72. Pitch Roof, 4, 5-'6. Trusses, 9, 46.Dimensions, 3, 23. Pitch Rivets, 58, Turning, 66, 89.Drift Pins, 70, 71. Pins, 17, 18, 19.

Process of Manuf'g, 74, Upsets. 63.Elastic Limit, 76, 87, 88. 82. Unit Strains, 13, 14, 15,Erection/41, 51, 90, 91,92, Phosphorus, 86. X6, 17, 18, 19, 20,_ 93, 94, 95- Punching, 55, 56, 57, 58. 21, 22, 59.Engineer, 72, 91, 92,93,94. Purlins, 8, 19, 22, 31,46, Valleys, 29.

C195- 47,48,49,50. Variation in Weight, 64.

Elongation, 77, 78, 87, 88, Purlin Spacing, 27, 48. Ventilation, 34,Purlin Clips, 31, 47-

Falsework 92. Water, 29; 34-Framing, 89. Rafters, 43. Webs, 17, 24, 43, 62,Flanges, 13, 15, 24. Reaming, 56, 71. Weight Material, 64.Flashing, 29. Redress, 72. Weight of Trusses, 9.Field Connections, 21. Rivets, 17, 18,55, 56, 57, Wind, 6, 7.Finish Angle, 33. 58, 67, 68, 69. Windows, 35.Finished Surfaces, 65. Rivet Holes, 55, 56, 57, Wrought Iron, 73, 74,Foundations, 3, 52, 53, 54- 67,68. 75) 76,, 77, 78, 79 ,

Foundries, 34. Ridges, 30, go gi.Risks, 93.

Girders, 13, 15, i 7 , 23, Roll Cap, 30.

24, 25. Rollers, 53*

OF T.HE

UN!VLK3ITY

;Jfj<-Covers 24" HlV **'

->l k- "Covers 4"

p<- E8"before Corrugating >| K 30"before Corrugating"-

j

(<W for sheets less than4>] Note -

Unsymmetrical sheets should

fer o-- ;-H

Louvre bars at panel pointsand 2.^4 for int. splice Corrug Louvres require an 8sheet

-plain Louvres 7i

CORRUGATED IRON, LOUVRES, FLASHING &c.

THIS BOOK IS DUE OK THE LAST DATESTAMPED BELOWAN INITIAL

YC 13045

GENERAL LIBRARY- U.C. BERKELEY

Boocmssss